Dias said most of the arrests were made Feb. 15, but added the operation was ongoing. He said heroin sales arrests for two more people were pending late Thursday.

Known as Operation Tar Block, the investigation began when undercover officers bought drugs from street-level dealers, Dias said. Those purchases, made in Monterey and Seaside, led police to alleged suppliers living in several Peninsula cities, he said.

Cody Esquivel, 27, of Seaside was arrested on suspicion of selling heroin. Timothy Murray, 41, of Marina and Castroville was arrested on gun charges and for allegedly possessing heroin and methamphetamine for sale.

Sepehr Makki, 18, of Pacific Grove and Joseph Sampognaro Jr., 24, of Monterey were arrested on a charge of offering to sell heroin.

Morgan Ferguson, 22, of Carmel was arrested on a charge of possessing heroin for sale, and Mike Sobel, 41, of Seaside was arrested and charged with possessing heroin and methamphetamine for sale.

Some of the arrests were made at the alleged dealers' residences in Seaside, Monterey, Marina and Castroville, Dias said.

He said heroin sales appeared to be drying up at the transit center — a small park with no facilities near the southern end of Alvarado Street in downtown Monterey — after the arrests.

"People started disappearing," he said. "The others noticed."

He said the operation illustrates the importance of having a Peninsula-wide task force that spans several cities.

"You can tell people about the importance of a regional task force, but this case really shows how something that happens in one city is connected to other places."